lecture_21 - along the sarcolemma Transverse tubules...

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Muscles Excitation-contraction coupling Mechanism of depolarization
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Excitation contraction coupling Depolarization Rise in intracellular [Ca 2+ ] Ca 2+ causes troponin and tropomyosin to move, allowing myosin to bind to actin Muscle contraction Muscles vary in terms of mechanism of the depolarization pattern of membrane potential over time propagation of the depolarization along the sarcolemma source of Ca 2+ Fig. 6.18/ 5.15
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Mechanism of depolarization Myogenic muscle vs. neurogenic muscle Fig. 5.26/ 4.26 Fig. 5.2/ 4.2 Motor end plate Fig. 6.27/ 5.25 Muscle cell Muscle cell
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Pattern of membrane potential over time Skeletal myofibers depolarize and repolarize very quickly Cardiomyocytes take longer to repolarize Fig. 6.26/ 5.24
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Propagation of the depolarization
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Unformatted text preview: along the sarcolemma Transverse tubules (T-tubules) help to conduct the action potentials deep into the muscle fiber Fig. 6.28/ 5.26 Source of Ca 2+ Ca 2+ can come from extracellular or intracellular stores At rest, Ca 2+ levels are kept low in cytoplasm Allowing Ca 2+ into the cytoplasm causes contraction Fig. 6.28/ 5.26 Source of Ca 2+ Intracellular stores Terminal cisternae: enlargements in sarcoplasmic reticulum to increase capacity for Ca 2+ Fig. 6.31/ 5.28 Transmission of signal from sarcolemma to sarcoplasmic reticulum Skeletal muscle depolarization-induced Ca 2+ release (Fig. 6.33/ 5.30) Cardiac muscle Ca 2+-induced Ca 2+ release (Fig. 6.32/ 5.29) Fig. 6.31/ 5.28...
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lecture_21 - along the sarcolemma Transverse tubules...

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